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Blood Nov 2022Platelet transfusions are commonly administered for the prevention or treatment of bleeding in patients with acquired thrombocytopenia across a range of clinical... (Review)
Review
Platelet transfusions are commonly administered for the prevention or treatment of bleeding in patients with acquired thrombocytopenia across a range of clinical contexts. Recent data, including randomized trials, have highlighted uncertainties in the risk-benefit balance of this therapy, which is the subject of this review. Hemovigilance systems report that platelets are the most frequently implicated component in transfusion reactions. There is considerable variation in platelet count increment after platelet transfusion, and limited evidence of efficacy for clinical outcomes, including prevention of bleeding. Bleeding events commonly occur despite the different policies for platelet transfusion prophylaxis. The underlying mechanisms of harm reported in randomized trials may be related to the role of platelets beyond hemostasis, including mediating inflammation. Research supports the implementation of a restrictive platelet transfusion policy. Research is needed to better understand the impact of platelet donation characteristics on outcomes, and to determine the optimal thresholds for platelet transfusion before invasive procedures or major surgery (eg, laparotomy). Platelet transfusion policies should move toward a risk-adapted approach that does not focus solely on platelet count.
Topics: Humans; Platelet Transfusion; Thrombocytopenia; Hemorrhage; Blood Platelets; Platelet Count
PubMed: 35926105
DOI: 10.1182/blood.2022016558 -
Veterinary Clinical Pathology Oct 2019Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder. The understanding of ITP pathogenesis is rapidly evolving. We now recognize ITP as a complex and... (Review)
Review
Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder. The understanding of ITP pathogenesis is rapidly evolving. We now recognize ITP as a complex and heterogeneous syndrome that results from a combination of humoral and cell-mediated attacks on platelets peripherally and megakaryocytes in the bone marrow. Autoantibody-mediated ITP also varies in the pathway used to clear platelets, which depends on the platelet glycoprotein being targeted. Moreover, ITP patients present with variable bleeding severities and treatment responses that do not closely correlate with platelet count. A gold standard diagnostic test for ITP is lacking, and biomarkers to assess disease severity are in their infancy. This review provides an update on the immunopathogenesis of ITP and summarizes currently available tests for ITP diagnosis, prediction of disease severity, and treatment responses. Given the heterogeneous pathogenesis and clinical presentation of ITP, we highlight the need for the development of diagnostic and prognostic tests that would allow for the individualized management of a complex disease.
Topics: Animals; Autoantibodies; Biomarkers; Blood Platelets; Bone Marrow; Hemorrhage; Megakaryocytes; Platelet Count; Prognosis; Purpura, Thrombocytopenic, Idiopathic
PubMed: 31538353
DOI: 10.1111/vcp.12774 -
Platelets Feb 2022Dengue virus (DENV) infection is responsible for the development of dengue illness, which can be either asymptomatic, present mild manifestations or evolve to severe... (Review)
Review
Dengue virus (DENV) infection is responsible for the development of dengue illness, which can be either asymptomatic, present mild manifestations or evolve to severe dengue. Thrombocytopenia is an important characteristic during DENV infection, being observed both in mild and severe dengue, although the lowest platelet counts are encountered during severe cases. This review gathers information regarding several mechanisms that have been related to alterations in platelet number and function, leading to thrombocytopenia but also platelet-mediated immune and inflammatory response. On this regard, we highlight that the decrease in platelet counts may be due to bone marrow suppression or consumption of platelets at the periphery. We discuss the infection of hematopoietic progenitors and stromal cells as mechanisms involved in bone marrow suppression. Concerning peripheral consumption of platelets, we addressed the direct infection of platelets by DENV, adhesion of platelets to leukocytes and vascular endothelium and platelet clearance mediated by anti-platelet antibodies. We also focused on platelet involvement on the dengue immunity and pathogenesis through translation and secretion of viral and host factors and through platelet-leukocyte aggregates formation. Hence, the present review highlights important findings related to platelet activation and thrombocytopenia during dengue infection, and also exhibits different mechanisms associated with decreased platelet counts.:Schematic mechanistic representation of platelet-mediated immune responses and thrombocytopenia during dengue infection. (A) DENV-infected platelets secrete cytokines and chemokines and also adhere to activated vascular endothelium. Platelets aggregate with leukocytes, inducing the secretion of NETs and inflammatory mediators by neutrophils and monocytes, respectively. (B) DENV directly infects stromal cells and hematopoietic precursors, including megakaryocytes, which compromises megakaryopoiesis. Both central and peripheric mechanisms contribute to DENV-associated thrombocytopenia.
Topics: Blood Platelets; Dengue; Dengue Virus; Female; Humans; Male; Platelet Count; Thrombocytopenia
PubMed: 34027810
DOI: 10.1080/09537104.2021.1921722 -
Clinica Chimica Acta; International... Nov 2022Acute leukemia (AL) is a hematological malignancy with high morbidity and mortality that is caused by abnormal hematopoietic stem cells. AL can change the parameters,... (Review)
Review
Acute leukemia (AL) is a hematological malignancy with high morbidity and mortality that is caused by abnormal hematopoietic stem cells. AL can change the parameters, quality, and function of platelets through numerous mechanisms, resulting in bleeding and even death in AL patients. Hence, AL patients are often clinically treated using normal platelet transfusion. However, studies have found that platelets can also affect AL cells. This review discusses the changes occurring in platelet count, mean platelet volume, platelet distribution width, reticulated platelets, platelet membrane glycoprotein, platelet aggregation, and activation in AL patients, the causes of these changes, and the possible significance of these changes for patient prognosis. The effects of platelets on the proliferation and drug resistance of AL cells are also discussed.
Topics: Acute Disease; Blood Platelets; Humans; Leukemia, Myeloid, Acute; Platelet Aggregation; Platelet Count; Platelet Membrane Glycoproteins
PubMed: 36122665
DOI: 10.1016/j.cca.2022.09.015 -
Current Opinion in Hematology Nov 2021This review highlights recent advancements in understanding the regulation of platelet numbers, focusing on mechanisms by which carbohydrates (glycans) link platelet... (Review)
Review
PURPOSE OF THE REVIEW
This review highlights recent advancements in understanding the regulation of platelet numbers, focusing on mechanisms by which carbohydrates (glycans) link platelet removal with platelet production in the bone marrow in health and disease.
RECENT FINDINGS
This review is focused on the role of carbohydrates, specifically sialic acid moieties, as a central mediator of platelet clearance. We discuss recently identified novel mechanisms of carbohydrate-mediated platelet removal and carbohydrate-binding receptors that mediate platelet removal.
SUMMARY
The platelet production rate by megakaryocytes and removal kinetics controls the circulating platelet count. Alterations in either process can lead to thrombocytopenia (low platelet count) or thrombocytosis (high platelet count) are associated with the risk of bleeding or overt thrombus formation and serious complications. Thus, regulation of a steady-state platelet count is vital in preventing adverse events. There are few mechanisms delineated that shed light on carbohydrates' role in the complex and massive platelet removal process. This review focuses on carbohydrate-related mechanisms that contribute to the control of platelet numbers.
Topics: Blood Platelets; Humans; Megakaryocytes; Platelet Count; Polysaccharides; Thrombopoiesis
PubMed: 34605444
DOI: 10.1097/MOH.0000000000000682 -
Breast Disease 2022The relationship between increased platelet count and cancer classification stage has long been established. The prevalence of thrombocytosis varies from 10% to 57% in...
INTRODUCTION
The relationship between increased platelet count and cancer classification stage has long been established. The prevalence of thrombocytosis varies from 10% to 57% in cancer patients. The pathogenesis of thrombocytosis in malignancy is uncertain. However, there is evidence that tumor cells secrete humoral factors that can cause thrombocytosis. Preoperative thrombocytosis is a poor prognostic variable in malignancies. This study investigated the correlation between platelet count and breast cancer stage.
METHODS
This cross-sectional study was conducted from February 2020 to January 2021. Patient data were collected from medical records. The study population comprised breast cancer patients at Dr. Wahidin Sudirohusodo Makassar. The staging examinations were based on the tumor, node, metastasis (TNM) classification according to the American Joint Committee on Cancer (AJCC) 8th Edition.
RESULTS
The study group comprised 171 breast cancer patients of varying ages. Metastasis was present in five (2.92%) patients and absent in 166 (97.8%) patients. Analyses found no statistically significant differences between the three staging groups based on the platelet count (p = 0.952).
CONCLUSION
There was no statistically significant relationship between increased platelet count and staging according to the TNM classification in breast cancer patients.
Topics: Humans; Female; Platelet Count; Breast Neoplasms; Cross-Sectional Studies; Retrospective Studies; Prognosis; Neoplasm Staging; Thrombocytosis
PubMed: 36641658
DOI: 10.3233/BD-229007 -
British Journal of Haematology Mar 2022Current therapies for immune thrombocytopenia (ITP) are successful in providing a haemostatic platelet count in over two-thirds of patients. Still, some patients have an... (Review)
Review
Current therapies for immune thrombocytopenia (ITP) are successful in providing a haemostatic platelet count in over two-thirds of patients. Still, some patients have an inadequate response and there is a need for other therapies. A number of novel therapies for ITP are currently being developed based upon the current pathophysiology of ITP. Many therapies are targetted at reducing platelet destruction by decreasing anti-platelet antibody production by immunosuppression with monoclonal antibodies targetted against CD40, CD38 and the immunoproteasome or physically reducing the anti-platelet antibody concentration by inhibition of the neonatal Fc receptor. Others target the phagocytic system by inhibiting FcγR function with staphylococcal protein A, hypersialylated IgG, polymeric Fc fragments, or Bruton kinase. With a recognition that platelet destruction is also mediated by complement, inhibitors of C1s are also being tested. Inhibition of platelet desialylation may also play a role. Other novel therapies promote platelet production with new oral thrombopoietin receptor agonists or the use of low-level laser light to improve mitochondrial activity and prevent megakaryocyte apoptosis. This review will focus on these novel mechanisms for treating ITP and assess the status of treatments currently under development. Successful new treatments for ITP might also provide a pathway to treat other autoimmune disorders.
Topics: Antibodies, Monoclonal; Blood Platelets; Humans; Infant, Newborn; Platelet Count; Purpura, Thrombocytopenic, Idiopathic; Thrombocytopenia; Thrombopoiesis
PubMed: 34611885
DOI: 10.1111/bjh.17872 -
American Journal of Obstetrics &... Jul 2023Many studies have reported the association between platelets and preeclampsia. However, sample sizes were small, and their findings were inconsistent. We conducted a... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Many studies have reported the association between platelets and preeclampsia. However, sample sizes were small, and their findings were inconsistent. We conducted a systematic review and meta-analysis to evaluate the association in pooled samples and in detail.
DATA SOURCES
A systematic literature search was performed using Medline, Embase, ScienceDirect, Web of Science, Cochrane Library, NICHD-DASH, LILACS, and Scopus from inception to April 22, 2022.
STUDY ELIGIBILITY CRITERIA
Observational studies comparing platelet count between women with preeclampsia and normotensive pregnant women were included.
METHODS
The mean differences with 95% confidence interval in platelet count were calculated. Heterogeneity was assessed using I statistics. Sensitivity and subgroup analyses were conducted. Statistical analysis was performed using RevMan 5.3 and ProMeta 3 software.
RESULTS
A total of 56 studies comprising 4892 preeclamptic and 9947 normotensive pregnant women were included. Meta-analysis showed that platelet count was significantly lower in women with preeclampsia than in normotensive controls (overall: mean difference, -32.83; 95% confidence interval, -40.13 to -25.52; P<.00001; I=92%; mild preeclampsia: mean difference, -18.65; 95% confidence interval, -27.17 to -10.14; P<.00001; I=84%; severe preeclampsia: mean difference, -42.61; 95% confidence interval, -57.53 to -27.68; P<.00001; I=94%). Significantly lower platelet count was also observed in the second trimester (mean difference, -28.84; 95% confidence interval, -44.59 to -13.08; P=.0003; I=93%), third trimester (mean difference, -40.67; 95% confidence interval, -52.14 to -29.20; P<.00001; I=92%), and before the diagnosis of preeclampsia (mean difference, -18.81; 95% confidence interval, -29.98 to -7.64; P=.009; I=87%), but not in the first trimester (mean difference, -15.14; 95% confidence interval, -37.71 to 7.43; P=.19; I=71%). Overall, the pooled sensitivity and specificity of platelet count were 0.71 and 0.77, respectively. The area under the curve was 0.80.
CONCLUSION
This meta-analysis confirmed that platelet count was significantly lower in preeclamptic women, irrespective of severity and presence or absence of associated complications, even before the onset of preeclampsia and in the second trimester of pregnancy. Our findings suggest that platelet count may be a potential marker to identify and predict preeclampsia.
Topics: Pregnancy; Female; Humans; Pre-Eclampsia; Platelet Count; Blood Pressure; Pregnancy Trimester, First; Pregnancy Trimester, Third
PubMed: 37098392
DOI: 10.1016/j.ajogmf.2023.100979 -
Platelets Dec 2023Platelets play a critical role in immune response. Coronavirus disease 2019 (COVID-19) patients with a severe course often show pathological coagulation parameters...
Platelets play a critical role in immune response. Coronavirus disease 2019 (COVID-19) patients with a severe course often show pathological coagulation parameters including thrombocytopenia, and at the same time the proportion of immature platelets increases. In this study, the platelet count and the immature platelet fraction (IPF) of hospitalized patients with different oxygenation requirements was investigated daily over a course of 40 days. In addition, the platelet function of COVID-19 patients was analyzed. It was found that the number of platelets in patients with the most severe course (intubation and extracorporeal membrane oxygenation (ECMO)) was significantly lower (111.5 ∙ 10 /mL) than in the other groups (mild (no intubation, no ECMO): 203.5 ∙ 10 /mL, < .0001, moderate (intubation, no ECMO): 208.0 ∙ 10 /mL, < .0001). IPF tended to be elevated (10.9%). Platelet function was reduced. Differentiation by outcome revealed that the deceased patients had a highly significant lower platelet count and higher IPF (97.3 ∙ 10 /mL, < .0001, 12.2%, = .0003).
Topics: Humans; COVID-19; Blood Platelets; Thrombocytopenia; Platelet Count; Blood Coagulation
PubMed: 36883692
DOI: 10.1080/09537104.2023.2184183 -
Journal of the American Society of... Feb 2024
Topics: Humans; Platelet Count; Blood Platelets; Case-Control Studies; Renal Insufficiency, Chronic
PubMed: 38300717
DOI: 10.1681/ASN.0000000000000268